A second former Polk County deputy faces prison for crimes involving the sheriff’s department. Kenneth Lane Gravett, 42, of Cedartown pleaded guilty today to mail fraud for filing a false theft report so he could collect an insurance claim on his Harley Davidson. Last month, Joshua David Lowe, 25, was sentenced to 21 months in prison for beating a jail inmate who had been strapped into a restraint chair. Read the news release on Gravett’s plea…